Standing wave particle beam accelerator

Abstract

An accelerator for accelerating a particle beam includes a main body having a plurality of electromagnetic cavities coupled in series, and a first coupling body having a first side cavity coupled to one of the electromagnetic cavities through a first opening, and to another of the electromagnetic cavities through a second opening, wherein the first opening and the second opening have different configurations. The accelerator further includes a pair of conductive capacitively coupled noses secured to side walls of the first coupling body, wherein the pair of noses have equal lengths.

1. An accelerator for accelerating a particle beam, comprising:
 a main body having a plurality of electromagnetic cavities coupled in series; 
 a first coupling body having a first side cavity coupled to two of the electromagnetic cavities, wherein the first side cavity is coupled to one of the two of the electromagnetic cavities through a first opening, and to another of the two of the electromagnetic cavities through a second opening, and wherein the first opening and the second opening have different sizes; and 
 a second coupling body coupled to the main body, the second coupling body having a second side cavity in communication with a third opening and a fourth opening, wherein the third and the fourth openings have a same size. 
 
   
   
     2. The accelerator of  claim 1 , wherein the first opening and the second opening have different cross sectional dimensions. 
   
   
     3. The accelerator of  claim 1 , wherein the first opening and the second opening have different cross sectional shapes. 
   
   
     4. The accelerator of  claim 1 , wherein the first opening has a first cross sectional area, the second opening has a second cross sectional area, and the first cross sectional area is approximately 5% to 20% larger than the second cross sectional area. 
   
   
     5. An accelerator for accelerating a particle beam, comprising:
 a main body having a plurality of electromagnetic cavities coupled in series; and 
 a first coupling body having a first side cavity coupled to one of the electromagnetic cavities through a first opening, and to another of the electromagnetic cavities through a second opening, wherein the first opening and the second opening have different sizes; 
 a second coupling body having a second side cavity coupled to the main body; and 
 an energy switch for changing an electric field distribution in the second side cavity. 
 
   
   
     6. The accelerator of  claim 5 , wherein the second side cavity is distal to a beam source, and the first side cavity is distal to the second side cavity. 
   
   
     7. The accelerator of  claim 5 , wherein the energy switch comprises a probe mounted for insertion into the second side cavity. 
   
   
     8. The accelerator of  claim 7 , wherein the diameter of the probe is selected to control an electric field distribution in the second side cavity. 
   
   
     9. The accelerator of  claim 7 , wherein varying a degree of insertion of the probe into the second side cavity changes an energy level of a x-ray beam generated by the accelerator. 
   
   
     10. The accelerator of  claim 5 , further comprising a gun source secured to a first end of the main body. 
   
   
     11. The accelerator of  claim 10 , wherein the first coupling body is not located between the first end and the second coupling body. 
   
   
     12. An accelerator for accelerating a particle beam, comprising:
 a main body having a plurality of electromagnetic cavities coupled in series along an axis; 
 a coupling body having a side cavity coupled to two of the electromagnetic cavities; and 
 an energy switch having only one probe for changing an electric field distribution in the side cavity; 
 wherein the probe has an axis that is parallel and offset from an axis of the coupling body, and varying a degree of insertion of the probe into the side cavity changes an electromagnetic field coupling between the two of the electromagnetic cavities. 
 
   
   
     13. The accelerator of  claim 12 , wherein the diameter of the probe is selected to control a frequency of the side cavity. 
   
   
     14. The accelerator of  claim 12 , wherein the probe has a lumen extending along its length. 
   
   
     15. The accelerator of  claim 14 , further comprising a fluid delivery tube disposed coaxially within the lumen of the probe. 
   
   
     16. The accelerator of  claim 14 , further comprising a choke coaxially surrounding at least a portion of the probe. 
   
   
     17. The accelerator of  claim 12 , further comprising a field step control for creating a desired electric field profile along the axis of the accelerator. 
   
   
     18. The accelerator of  claim 17 , wherein the side cavity is distal to a beam source, and the field step control is distal to the side cavity. 
   
   
     19. An accelerator for accelerating a particle beam, comprising:
 a main body having a plurality of electromagnetic cavities coupled in series along an axis; and 
 a device for generating a desired electric field profile along the axis to control separation of resonant modes of the electromagnetic cavities; wherein the device comprises: 
 a coupling body having a cavity that couples to one of the electromagnetic cavities through a first opening, and to another of the electromagnetic cavities through a second opening, wherein the first and the second openings have different sizes; and 
 a pair of conductive capacitively coupled noses secured to side walls of the coupling body, the pair of noses having equal lengths in a direction of the axis. 
 
   
   
     20. The accelerator of  claim 1 , further comprising:
 a ring structure secured to a dividing wall that separates two of the electromagnetic cavities. 
 
   
   
     21. An accelerator for accelerating a particle beam, comprising:
 a main body having a plurality of electromagnetic cavities coupled in series along an axis; and 
 a device for generating a desired electric field profile along the axis to control separation of resonant modes of the electromagnetic cavities; wherein the device comprises a dividing wall that separates two of the electromagnetic cavities, and a beam aperture for allowing the particle beam to travel therethrough, the beam aperture having a cross sectional dimension that is different from that of an adjacent beam aperture. 
 
   
   
     22. An accelerator for accelerating a particle beam, comprising:
 a main body having a plurality of electromagnetic cavities coupled in series; 
 a first coupling body having a first side cavity coupled to two of the electromagnetic cavities, wherein the first side cavity is coupled to one of the two of the electromagnetic cavities through a first opening, and to another of the two of the electromagnetic cavities through a second opening, wherein the first opening and the second opening have different shapes; and 
 a second coupling body coupled to the main body, the second coupling body having a second side cavity in communication with a third opening and a fourth opening, wherein the third and the fourth openings have a same shape. 
 
   
   
     23. The accelerator of  claim 22 , further comprising a pair of conductive capacitively coupled noses secured to side walls of the first coupling body. 
   
   
     24. The accelerator of  claim 22 , wherein the first opening and the second opening have different cross sectional dimensions. 
   
   
     25. The accelerator of  claim 22 , wherein the first opening has a first cross sectional area, the second opening has a second cross sectional area, and the first cross sectional area is approximately 5% to 20% larger than the second cross sectional area. 
   
   
     26. An accelerator for accelerating a particle beam, comprising:
 a main body having a plurality of electromagnetic cavities coupled in series; and 
 a first coupling body having a first side cavity coupled to one of the electromagnetic cavities through a first opening, and to another of the electromagnetic cavities through a second opening, wherein the first opening and the second opening have different shapes; 
 a second coupling body having a second side cavity coupled to the main body; and 
 an energy switch for changing an electric field distribution in the second side cavity. 
 
   
   
     27. The accelerator of  claim 1 , further comprising a pair of conductive capacitively coupled noses secured to side walls of the first coupling body, wherein the pair of noses have equal lengths. 
   
   
     28. The accelerator of  claim 1 , wherein the one of the electromagnetic cavities and the another of the electromagnetic cavities have a same shape. 
   
   
     29. The accelerator of  claim 12 , wherein the two of the electromagnetic cavities have a same shape. 
   
   
     30. The accelerator of  claim 19 , wherein the one of the electromagnetic cavities and the another of the electromagnetic cavities have a same shape. 
   
   
     31. The accelerator of  claim 1 , wherein the second coupling body is coupled to another two of the plurality of electromagnetic cavities, the second side cavity of the second coupling body coupled to one of the another two of the electromagnetic cavities through the third opening, and to another of the another two of the electromagnetic cavities through the fourth opening. 
   
   
     32. The accelerator of  claim 22 , wherein the second coupling body is coupled to another two of the plurality of electromagnetic cavities, the second side cavity of the second coupling body coupled to one of the another two of the electromagnetic cavities through the third opening, and to another of the another two of the electromagnetic cavities through the fourth opening. 
   
   
     33. The accelerator of  claim 20 , wherein the dividing wall has an aperture for allowing the particle beam to travel therethrough, and wherein the ring structure has an opening that is in communication with the aperture.